This invention very simply constitutes a modification of use with minimal fabrication changes of the original device as defined in U.S. Pat. No. 5,256,132 (Snyders) which invention is designed for acute heart failure support via a cyclical pneumatic ventricular compression in timed synchrony with the ambient heart rhythm. The present methodology pertains to the provision of long-term support for individuals suffering from certain late-stage heart failure disease entities as are particularly known in medical practice as the dilated cardiomyopathies. These disease states are of frequent occurrence and carry a high mortality rate if not corrected in a reasonable period of time. This modification consists of the instillation of a high viscosity silicone (or other) fluid into the encircling retention sac space of the previously described device (U.S. Pat. No. 5,256,132) to enclose the heart ventricles, with a resultant reduction in ventricular systolic and diastolic volumes of the heart. Such volume reductions are known to reduce myocardial oxygenation requirements for any given level of cardiac contractility needed for ongoing adequate cardiac functional requirements for any given level of physical activity by the patient. Such a modification and application of the previously described VAD (Ventricular Assist Device), though minimally changed in its original fabrication, could open a new area of interventional long-term support for those patients afflicted with a dilated cardiomyopathy.
The VAD jacket is quite easily adjustable to any cardiac size and is virtually self-sizing relative to circumferential dimension requirements even for the very largest hearts because of the diminutive fabrication features of the device for insertion around the heart and inside the pericardial sac, which location is its appropriate compliant anatomical site of implantation. Subsequent filling of the sac space with a viscous silicone or other equivalent non-compressible fluid through the fill line of the device to enclose the ventricular masses with either no or minimal pressurization therein as registered in a sac pressure monitor line then results in a viscous cardioplasty reinforcement of the thinned ventricular walls with a resultant reduction in LV (Left Ventricular) and RV (Right Ventricular) diameters to effect a desirable reduction of wall stress. This procedure thus effectively provides for a "reverse remodeling" of the heart via both a diastolic and systolic volumetric restriction but not constriction of the ventricular anatomy and with a subsequent improved physiological benefit to cardiac function.
The Law of LaPlace defines that this physiological benefit is sequential to reduced wall stress (wall tension) consequent upon the reduction in chamber diameter and increased chamber wall thickness provided by such a girdling "cardioplasty" event, and such an alteration results in reduced myocardial oxygen needs sequential to that reduction in wall stress. Such reduced oxygen needs at rest then convert to increased myocardial oxygen availability for increased physical activity and a resultant improved functional class for the patient. It will be noted below that an important provision of a high viscosity fluid (e.g. to 12,500 ctsk.) for sac filling is suggested for use because of the increased inertial character of those higher viscosity fluids such that areas of ventricular akinesia or dyskinesia subject to paradoxical wall motion in systole should be somewhat restrained from such an undesirable dysfunctional event with the ventricular wall enclosure as proposed. Such restraint would provide a beneficial improvement in systolic ejection volumes and thus be additive to the beneficial girdling restraint derived from the cardioplasty jacket application itself.